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To all whom it may comm:

Be it known that I, RALPH H. MoKnn, a. citizen of the United States,residin at New York city in the county of New ork and State of hlewYork, have invented certain new and useful Improvements in Processes ofMaking Hydrogen and Zinc Oxid, of which the following is e s cification.

This invention is 9. nova process whereby I am enabled to reduce in asingle operation zinc oxid oi excellent color and: free from uuoxidizeclzinc or blue-powder, and hydrogen gas, the latter unmixed with oxide ofcarbon or such other impurities as are highly detrimental for certainpurposes, as or example when the hydrogen is to be em loyed inconjunction with nitron for the catalytic synthesisof ammonia.

n this met-mentioned operation, for example, it is now well recognizedthat even minute traces of carbon monoxid in the hydrogen act ascatalyst poisons; and it is one of the edvantagesof my improved proce sthat it yields hydrogen which is substantially pure, even when tested inaccordance with the very strict requirements of the ammoniaeynthesisprocess. My process is based upon the known reaction whereby water invapor phase is deoxidized by metallic zinc in accordance with a reliction which may be expressed as follows:

Zn +13 0 ="ZIlO-l-Iil As heretofore practised, however the zinc oxidproduced has been of in erior quality, due in part to incompleteoxidation of the metal and in part to objectionable physicalcharacteristics. According to my process I obtain the oxid directly inthe form of a fine powder of uniform quality and quite free fromunoxidized zinc.

I accomplish this by first vaporizing carhon-free metallic zinc in anysuitable furnace of the retort type, in which the vapors of zinc willnot be contaminated with oxide of carbon, and then reacting upon thezinc temperature. and in decided excess of'the reaction requirements.This use of steam in excess presents a double advantage, in that first.the excess of steam, acting at a suitable temperature upon the vapors ofzinc, effects the complete oxidation of the Zn to ZnO; and second, theunreacted ex- Bpecifleetlon of Letters Patent. Application em Februarya, 1m; man He. amass.

Patented Oct. 19, 1920.

cess of steam, functioning as an inert carrrer for the oxid, not onlyprevents any tendency to the reduction of the oxid by hydrogen through areversal of the reaction of ox1detion, but also brings about thedeposition of the zinc oxid in a physical state of minute subdivisionwhich is highly advantageous from the int of view of its commercial usesin points, etc.

The immediate product of the reaction is a mixture of zinc oxid inminute subdivision, steam and hydro This mixture may be treated in anyesired way for the separation of the components. Preferably it is cooledto a temperature somewhat in excess of 100 C. and filtered through bagsor equivalent devices, whereby the zinc is directly collected intho formof a dry powder. The mixture of steam with hydrogen is then furthercooled in order to condense the steam, leaving the hydrogen in a stateof substantial purity.-

Other inert nurses may be used as diluents to assnre the deposition ofthe zinc oxid in the desirable physical state mentioned above. Of suchgases. it is particularly advantagoons to employ nitrogen, especiallywhen the hydrogen produced by the reaction is to be utilized inadmixture with nitrogen in the ammonia synthesis.

Prior to the introduction of the steam into the vapor of zinc, theformer is preferably superheated to or above the temperature of the zincvapors, the purpose being to avoid any sudden chilling of the lattersuch as would tend to the precipitation of bluepowdor in admixture withthe oxid.

It is important for the best results that the reaction whereby the zincoxid is formed should be wholly with zinc in the vapor phase, since inthis way only can an oxid of uniform physical character he obtained.Although zinc in-liquid phase will decompose water vapor. the resultingoxid does not possess the desirable characteristics of that derived fromthe vapor-phase reaction; and if the reaction occurs with zinc partly inthe liquid phase and partly in vapor phfsgl, a non-uniform productresults.

1. Process of preparing pure zinc oxid and hydrogen free fromcarbonaceous impurities, comprising bringing substantially pure zinc invapor phase into reactive relntion with steam, the latter in suflicientex- 3. Process of preparing pure zinc oxid cess of the reactingproportions to secure and hydrcgen, comprising bringi zinc insubstantially complete oxidation of the zinc. vapor phase into reactivere etion with 10 2. Process of preparing pure zinc oxid steam, inpresence of nitro en. 5 and hydrogen, comprising brin ing zinc in Intestimony whereof,I a 1: my signature.

vapor phase into reactive re atlon with steam, in presence of an inertdiluent. RALPH H. MUKEE.

